The concept of using discrete track magnetic media to increase areal density or increase component tolerances has received much attention recently. Claimed benefits are a signal to noise ratio (SNR) increase of 0.2 to 3 dB due to a wider read area and reduced track edge noise, and a reader width tolerance that is increased by >100%. Several types of discrete track media (DTM) architectures have been previously modeled and/or fabricated including: (1) topographically defined (spacing loss); (2) selective etch or deposition defined (using a discontinuous recording layer); and (3) selective disordering defined (which alters the magnetic properties of the recording layer).
Although the analysis is far from complete, the benefits from most of the current DTM architectures seem too small to justify the increased media cost and the system impacts. DTM can be used for perpendicular recording, wherein the direction of magnetization in the media is perpendicular to the plane of the media. An issue facing perpendicular recording is the spreading of the magnetic write field beyond the desired recording zones. This causes adjacent track erasures unless the field is contained using recording head side shields. Unfortunately these side shields steal flux from the recording zone.
There is a need for an improved discrete track media that has the benefits of conventional DTM, while addressing some of the manufacturability and tribology concerns, and alleviating the need for side shields in the recording head.